1. Field of the Invention
The present invention relates to a processing method and a processing system. In particular, the present invention relates to a processing method and a processing system each for accurately nondestructively evaluating by Scatterometry a surface structure of a workpiece after predetermined processing and for controlling processing conditions based on the evaluated surface structure.
2. Description of the Related Art
In these days, the semiconductor integrated circuits are increasing reduced in size, giving rise to a need for forming the circuit pattern on a wafer surface more finely. To form such a finer circuit pattern, it is necessary to accurately evaluate the structure of the wafer surface, for example, the structure of the wafer surface after an etching processing or the like at the manufacturing process step.
Conventionally, to evaluate the structure of the wafer surface after the etching processing, such a method has mainly been taken that the cross section of a cleaved wafer is observed under a scanning electron microscope (SEM) and photographed. This method, however, has a disadvantage that the wafer itself needs to be broken to form a wafer cross section that is observation object.
Hence, in order to nondestructively evaluate the structure of the wafer surface after the etching processing, the present inventor considered whether Scatterometry such as Reflectometry, Ellipsometry, or the like which have conventionally been used for evaluation or the like of a resist pattern formed on the wafer surface is applicable to evaluation of the structure of the wafer surface after the etching processing (see, for example, Japanese Patent Application Laid-open No. 2002-260994).
However, since the wafer surface after the etching processing has unnecessary portions with various shapes and compositions, such as a polymer attached to the surface, a damaged layer formed within the surface region of a wafer W, and a deteriorated layer and a hard layer formed within the surface region of a resist, and so on, its optical constant n value (refractive index) and k value (absorption coefficient) cannot be specified.
It is difficult to evaluate by Scatterometry such a surface structure of the wafer W whose optical constant cannot be specified.
Besides, a concrete method for evaluating the surface structure of a wafer and a concrete control method of processing conditions based on the evaluation are still undeveloped.